U.S. patent application number 16/979811 was filed with the patent office on 2021-04-15 for full-duplex communication method in high efficient wireless lan network and station apparatus.
This patent application is currently assigned to SENSCOMM SEMICONDUCTOR CO., LTD.. The applicant listed for this patent is SENSCOMM SEMICONDUCTOR CO., LTD.. Invention is credited to Seung Ho CHOO, Jin Won KANG, Dae Hong KIM, Sang Min SHIM.
Application Number | 20210111858 16/979811 |
Document ID | / |
Family ID | 1000005305467 |
Filed Date | 2021-04-15 |
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United States Patent
Application |
20210111858 |
Kind Code |
A1 |
CHOO; Seung Ho ; et
al. |
April 15, 2021 |
FULL-DUPLEX COMMUNICATION METHOD IN HIGH EFFICIENT WIRELESS LAN
NETWORK AND STATION APPARATUS
Abstract
A full-duplex communication method in a high efficiency wireless
local area network (WLAN), the full-duplex communication method
being performed by an access point (AP) in a WLAN network, includes
transmitting a reference frame to at least one station (STA);
receiving an uplink frame from the at least one STA in a time
period determined on the basis of the reference frame; and
transmitting a downlink frame to the at least one STA in a specific
time duration of the time period, wherein the uplink frame and the
downlink frame are transmitted through the same channel.
Inventors: |
CHOO; Seung Ho; (Irvine,
CA) ; KANG; Jin Won; (Tustin, CA) ; SHIM; Sang
Min; (Irvine, CA) ; KIM; Dae Hong; (Irvine,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SENSCOMM SEMICONDUCTOR CO., LTD. |
Suzhou, Jiangsu |
|
CN |
|
|
Assignee: |
SENSCOMM SEMICONDUCTOR CO.,
LTD.
Suzhou, Jiangsu
CN
|
Family ID: |
1000005305467 |
Appl. No.: |
16/979811 |
Filed: |
March 12, 2019 |
PCT Filed: |
March 12, 2019 |
PCT NO: |
PCT/CN2019/077735 |
371 Date: |
September 10, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62641832 |
Mar 12, 2018 |
|
|
|
62641862 |
Mar 12, 2018 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 72/0446 20130101;
H04L 5/1469 20130101; H04W 84/12 20130101 |
International
Class: |
H04L 5/14 20060101
H04L005/14; H04W 72/04 20060101 H04W072/04 |
Claims
1. A full-duplex communication method in a high efficiency wireless
local area network (WLAN), the full-duplex communication method
being performed by an access point (AP) in a WLAN network, the
method comprising: transmitting a reference frame to at least one
station (STA); receiving an uplink frame from the at least one STA
in a time period determined on the basis of the received reference
frame; and transmitting a downlink frame to the at least one STA in
a specific time duration of the time period, wherein the uplink
frame and the downlink frame are transmitted through the same
channel.
2. The full-duplex communication method of claim 1, wherein the AP
transmits the downlink frame to the solicited STA which transmits
the uplink frame.
3. The full-duplex communication method of claim 1, wherein the AP
transmits the downlink frame to unsolicited STA.
4. The full-duplex communication method of claim 1, wherein the
reference frame includes a triggered response scheduling (TRS)
control field.
5. The full-duplex communication method of claim 1, wherein the
uplink frame is a High-Efficiency Trigger-Based (HE TB) PPDU.
6. The full-duplex communication method of claim 1, wherein the
uplink frame comprises a pre-HE modulated field and an HE modulated
field, and wherein specific time duration is included in a time
period in which the HE modulated field is received.
7. The full-duplex communication method of claim 1, wherein the
specific time duration is a period after a training sequence for
the uplink frame is processed in the AP.
8. The full-duplex communication method of claim 1, wherein the
downlink frame and the uplink frame are transmitted in different
resource units (RUs) respectively.
9. The full-duplex communication method of claim 1, wherein the
downlink frame and the uplink frame are transmitted in a common
resource unit (RU).
10. A full-duplex communication method in a high efficiency
wireless local area network (WLAN), the full-duplex communication
method being performed by a specific station (STA) in a WLAN
network, the method comprising: receiving a reference frame from an
access point (AP); and receiving a downlink frame from the AP in a
specific time duration of a time period determined by the reference
frame, wherein the reference frame is transmitted to a plurality of
STAs including the specific STA, the time period is a period in
which at least one of the plurality of STAs is solicited to
transmits an uplink frame to the AP, and the uplink frame and the
downlink frame are transmitted through the same channel.
11. The full-duplex communication method of claim 10, wherein the
uplink frame is a High-Efficiency Trigger-Based (HE TB) PPDU.
12. The full-duplex communication method of claim 10, wherein the
uplink frame comprises a pre-HE modulated field and an HE modulated
field, and the specific time duration is included in a time period
in which the HE modulated field is received.
13. The full-duplex communication method of claim 10, wherein the
downlink frame and the uplink frame are transmitted in different
resource units (RUs) respectively.
14. The full-duplex communication method of claim 10, wherein the
downlink frame and the uplink frame are transmitted in a common
resource unit (RU).
15. A station apparatus for performing full-duplex communication in
a high efficiency wireless local area network (WLAN), the station
apparatus comprising: a communication device configured to receive
a reference frame from an access point (AP) in a WLAN and receive a
downlink frame from the AP in a specific time duration of a time
period; and a processor configured to determine the time period or
the specific time duration based on the reference frame and process
the downlink frame transmitted in the specific time duration,
wherein the reference frame is transmitted to a plurality of
stations including the station apparatus, the [time period is a
period in which at least one of the plurality of stations transmits
an uplink frame to the AP, and the uplink frame and the downlink
frame are transmitted through the same channel.
16. The station apparatus of claim 15, wherein the communication
device transmits a High-Efficiency Trigger-Based (HE TB) PPDU to
the AP as the uplink frame.
17. The station apparatus of claim 15, wherein the uplink frame
comprises a pre-HE modulated field and an HE modulated field, and
the specific time duration is included in a time period in which
the HE modulated field is received.
18. The station apparatus of claim 15, wherein the downlink frame
and the uplink frame are transmitted in individual resource units
(RUs) respectively.
19. The station apparatus of claim 15, wherein the downlink frame
and the uplink frame are transmitted in a common resource unit
(RU).
Description
CROSS-REFERENCE TO PRIOR APPLICATIONS
[0001] This application is a National Stage Patent Application of
PCT International Patent Application No. PCT/CN2019/077735 (filed
on Mar. 12, 2019) under 35 U.S.C. .sctn. 371, which claims priority
to U.S. Provisional Application Nos. 62/641,832 (filed on Mar. 12,
2018) and 62/641,862 (filed on Mar. 12, 2018), which are all hereby
incorporated by reference in their entirety.
BACKGROUND
[0002] The following description relates to a technique for
performing in-band full-duplex communication in a high-efficiency
wireless local area network (WLAN).
[0003] In a wireless local area network (WLAN), a single basic
service set (BSS) is composed of two kinds of entities which are a
single AP Station (STA) and multiple non-AP STAs. STAs share a same
radio frequency channel with one out of WLAN operation bandwidth
options (e.g. 20/40/80/160 MHz). Here, AP STA and non-AP STA could
be referred as AP and STA, respectively.
[0004] the legacy IEEE 802.11a/b/g/n/ac standard does not guarantee
communication stability in dense environments with many users. In
order to overcome this limit, the High-Efficiency WLAN Study Group
(HEW SG) and the IEEE Task Group ax (TGax) were formed by IEEE
802.11 working group, which has worked on the standardization of
IEEE 802.11ax as the next generation WLAN standard in 2019. The
IEEE 802.11ax standard aims to improve system throughput in dense
environments with many APs and STAs.
SUMMARY
[0005] Full-duplex (FD) communication is one of promising
next-generation wireless technologies. This technology enables up
to double network throughput ideally because the information can be
transmitted and received between wireless communication nodes
through the same channel at the same time. In recent FD
communication becomes more feasible thanks to the enhancement of
self-interference cancellation (SIC) technology.
[0006] The following description is intended to provide full-duplex
communication between an AP and an STA in an IEEE 802.11ax
environment.
[0007] The following description enables full-duplex communication
in the IEEE 802.11ax environment while maintaining backward
compatibility with the IEEE 802.11 standards (802.11a/b/g/n/adax).
The following description provides a communication protocol for
avoiding interference between an uplink signal and a downlink
signal that are carried through the same channel at the same time
in IEEE 802.11ax.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 illustrates an example of a basic service set in a
wireless local area network (WLAN).
[0009] FIG. 2 illustrates example resources used for WLAN
communication.
[0010] FIG. 3 illustrates an example PHY PPDU packet format defined
in 802.11ax.
[0011] FIG. 4 illustrates an example communication process between
an access point (AP) and a station (STA) in 802.11ax.
[0012] FIG. 5 illustrates an example process of performing
full-duplex communication in a WLAN environment.
[0013] FIG. 6 illustrates another example process of performing
full-duplex communication in a WLAN environment.
[0014] FIG. 7 illustrates still another example process of
performing full-duplex communication in a WLAN environment.
[0015] FIG. 8 illustrates an example packet for full-duplex
communication.
[0016] FIG. 9 illustrates example resources to be allocated for
full-duplex communication.
[0017] FIG. 10 illustrates example resource allocation for
full-duplex communication.
[0018] FIG. 11 illustrates an example reference frame.
[0019] FIG. 12 illustrates an example block diagram of an AP and an
STA.
[0020] Throughout the drawings and the detailed description, unless
otherwise described, the same drawing reference numerals will be
understood to refer to the same elements, features, and structures.
The relative size and depiction of these elements may be
exaggerated for clarity, illustration, and convenience
DETAILED DESCRIPTION
[0021] The following detailed description is provided to assist the
reader in gaining a comprehensive understanding of the methods,
apparatuses, and/or systems described herein. Accordingly, various
changes, modifications, and equivalents of the systems, apparatuses
and/or methods described herein will be suggested to those of
ordinary skill in the art. Also, descriptions of well-known
functions and constructions may be omitted for increased clarity
and conciseness.
[0022] The presently described examples will be understood by
reference to the drawings, wherein like parts are designated by
like numerals throughout. The drawings are not necessarily drawn to
scale, and the size and relative sizes of the layers and regions
may have been exaggerated for clarity.
[0023] It will be understood that, although the terms first,
second, A, B, etc. may be used herein to describe various elements,
these elements should not be limited by these terms. These terms
are only used to distinguish one element from another. For example,
a first element could be termed a second element, and, similarly, a
second element could be termed a first element, without departing
from the scope of the present invention. As used herein, the term
"and/or" includes any and all combinations of one or more of the
associated listed items.
[0024] As used herein, the singular forms "a," "an" and "the" are
intended to include the plural forms as well, unless the context
clearly indicates otherwise. It will be further understood that the
terms "comprises," "comprising," "includes" and/or "including,"
when used herein, specify the presence of stated features,
integers, steps, operations, elements, and/or components, but do
not preclude the presence or addition of one or more other
features, integers, steps, operations, elements, components, and/or
groups thereof.
[0025] Before starting detailed explanations of figures, components
that will be described in the specification are discriminated
merely according to functions mainly performed by the components or
conventionally carried out according to common knowledge of related
technical fields. That is, two or more components which will be
described later can be integrated into a single component.
Furthermore, a single component which will be explained later can
be separated into two or more components. Moreover, each component
which will be described can additionally perform some or all of a
function executed by another component in addition to the main
function thereof. Some or all of the main function of each
component which will be explained can be carried out by another
component. Accordingly, presence/absence of each component which
will be described throughout the specification should be
functionally interpreted.
[0026] The following description applies to a wireless local area
network (WLAN). The following description may apply to the next
generation WLAN method (IEEE 802.11ax) or the like. The IEEE
802.11ax maintains compatibility with the conventional IEEE
802.11a/b/g/n/ac. The following description may be executed in the
IEEE 802.11ax environment, and also maintains compatibility with
the conventional IEEE 802.11a/b/g/n/ac.
[0027] The following description relates to in-band full-duplex
communication. The following description may basically apply to the
IEEE 802.11ax. However, the following description does not
necessarily limitedly apply to the IEEE 802.11ax. Therefore, the
following description may apply to WLAN standards that will emerge
after the IEEE 802.11ax.
[0028] Terms used herein will be defined.
[0029] A WLAN or a next generation WLAN basically refers to a
communication network operating according to a protocol defined in
the IEEE 802.11ax. A conventional WLAN refers to a WLAN according
to a standard prior to the IEEE 802.11ax.
[0030] An access point (AP) is an apparatus that provides access to
the distribution system services and mostly is connected to the
Internet to provide a wireless channel in a certain coverage area.
The apparatus is hereinafter referred to as an AP station or an
AP.
[0031] A non-AP station (STA) is an apparatus that communicates the
information through a certain wireless channel allocated by an AP.
The apparatus is hereinafter referred to as a station or an
STA.
[0032] A signal transmitted by an AP to an STA is called a downlink
signal. The downlink signal may be composed of at least one frame.
The frame included in the downlink signal is called a downlink
frame.
[0033] A signal transmitted by an STA to an AP is called an uplink
signal. The uplink signal may be composed of at least one frame.
The frame included in the uplink signal is called an uplink
frame.
[0034] The full-duplex communication basically refers to in-band
full-duplex transmission and reception concurrently using the same
channel.
[0035] The IEEE 802.1 lax is well known as High Efficiency WLAN (HE
WLAN). A Physical Protocol Data Unit (PPDU) is newly defined in the
IEEE 802.11ax PHY. Examples of the PHY PPDU for data transmission
include High Efficiency Single User Physical Protocol Data Unit (HE
SU PPDU), High Efficiency Multi User Physical Protocol Data Unit
(HE MU PPDU), High Efficiency extended range Single User Physical
Protocol Data Unit (HE ER SU PPDU) and High Efficiency Trigger
Based Physical Protocol Data Unit (HE TB PPDU).
[0036] First, the WLAN and the IEEE 802.11ax will be described
briefly below.
[0037] FIG. 1 illustrates an example basic service set (BSS) in a
wireless local area network (WLAN). A BSS may include one AP and at
least one STA. FIG. 1 illustrates an example of a WLAN BSS 100
including a single AP 110 and a plurality of STAs 120. For
convenience of description, it is assumed that a single BSS
includes a plurality of STAs. Any one of the plurality of STAs 120
receives resources allocated for wireless communication and
communicates with the AP 110. The AP 110 delivers information
regarding the resource allocation to the STA.
[0038] FIG. 2 illustrates example resources used for WLAN
communication. In FIG. 2, one rectangular block refers to a
resource allocated to one STA.
[0039] FIG. 2A illustrates Orthogonal Frequency Division Multiple
(OFDM) used in the conventional IEEE 802.11. A conventional WLAN
has a frame exchange performed in Time Division Multiple Access
(TDMA). STAs share any one wireless frequency channel in ISM band.
Only one user (STA) occupies a specific channel in a specific time
period.
[0040] FIG. 2B illustrates Orthogonal Frequency Division Multiple
Access (OFDMA) modulation technology was employed newly in the IEEE
802.11ax. In OFDMA, one wireless channel can be composed of one or
multiple resource units and the IEEE 802.11ax defines RU as a
minimum allocation unit which is a group of subcarriers. The OFDMA
enables multi-user transmission using frequency orthogonal division
in the same time period. Any one user (STA) may use one RU in a
specific time period. The AP may allocate different RUs to one or a
plurality of STAs in a WLAN packet. Alternatively, the AP may
separate spatial streams in a specific RU to allocate resources to
any one or a plurality of STAs. The OFDMA provides more dynamic
resource allocation to multiple users than the OFDM.
[0041] FIG. 3 illustrates an example PHY PPDU packet format newly
defined in 802.11ax. The PPDUs in FIG. 3 are as follows: HE SU
PPDU; HE MU PPDU; HE ER SU PPDU; and HE TB PPDU. The formats are
shown in FIG. 3. Details of fields constituting each of the formats
shown in FIG. 3 are shown in Table 1 below. Detailed descriptions
of the fields will be omitted. The HE TB PPDU will be described
below with reference to FIG. 8.
TABLE-US-00001 TABLE 1 Field Description L-STF Non-HT Short
Training field L-LTF Non-HT Long Training field L-SIG Non-HT SIGNAL
field RL-SIG Repeated Non-HT SIGNAL field HE-SIG-A HE SIGNAL A
field HE-SIG-B HE SIGNAL B field HE-STF HE Short training field
HE-LTF HE Long Training field Data The Data field carrying the
PSDU(s) PE Packet
[0042] FIG. 4 illustrates an example communication process between
an AP and multiple STAs in 802.11ax. FIG. 4 illustrates an example
communication process in a BSS in which there are a single AP and
`n` number of STAs. This example will be described in time order.
FIG. 4 describes a multi-user (MU) scenario as an example.
[0043] The AP transmits a Multi-User Request-to-Send (MU-RTS) frame
to STA 1 and STA n at time T=t0. In response to the MU-RTS frame,
STA 1 and STA n commence a Clear-to-Send (CTS) frame at time T=t1.
After receiving the CTS response successfully, the AP can perform
the following steps. The MU-RTS/CTS exchange corresponds to a
pre-operation for WLAN data transmission. This process is optional,
and thus may not be an operation that must be performed before a DL
MU PPDU.
[0044] The AP transmits a frame including resource allocation
information to solicited STAs. The AP transmits a DL MU PPDU to
solicited STAs, herein, STA 1 and STA n at time T=t2. The DL MU
PPDU may include a trigger frame or the DL MU PPDU may include a
triggered response scheduling (TRS) control field. In response to
the DL MU PPDU, STA 1 and STA n transmit an HE TB PPDU at time T=t3
as a response frame along with an ACK. The solicited STAs transmit
the HE TB PPDU using allocated RU respectively.
[0045] The AP may transmit a BlockAck frame in response to the
reception of the HE TB PPDU. This kind of transmission of the
BlockAck frame may be optional.
[0046] By repeating the above communication process, the AP may
communicate with a plurality of STAs.
[0047] Full-duplex communication applicable to a WLAN environment
such as 802.11ax will be described below. It is assumed that an AP
and STA which will be mentioned support IEEE 802.11ax.
[0048] FIG. 5 illustrates an example process of performing
full-duplex communication in a WLAN environment. FIG. 5A
illustrates a BSS 200 that performs full-duplex communication in a
WLAN environment. The BSS 200 includes a single AP 210 and n number
of STAs 220-1, 220-2, . . . , 220-n. The AP 210 is an AP capable of
full-duplex communication (hereinafter referred to as an FD-capable
AP). The FD-capable AP may be an AP having a function of cancelling
self-interference (SI) caused by a signal transmitted by the AP
itself. The SI cancellation technology can be implemented in
various ways.
[0049] FIG. 5B illustrates an example for a full-duplex
communication in the BSS 200. This example will be described in
time order. The AP 210 transmits a reference frame to STA 1 220-1
and STA n 220-n. The reference frame may be the above-described
trigger frame. Also, the reference frame may include a TRS control
field. The reference frame may include RU allocation information
for OFDMA communication.
[0050] When the reference frame is received, solicited STA 1 220-1
and STA n 220-n transmit an HE TB PPDU through allocated RUs. STA 1
220-1 and STA n 220-n may transmit an HE TB PPDU to the AP in the
same time period. STA 1 220-1 and STA n 220-n may transmit an HE TB
PPDU at a certain timing on the basis of the received reference
frame. That is, STA 1 220-1 and STA n 220-n may synchronize frames
to be transmitted by using the timing of the received reference
frame end.
[0051] Meanwhile, the AP 210 may transmit a certain frame to STA 2
220-2 at or within the same time period in which STA 1 220-1 and
STA n 220-n transmit an HE TB PPDU. Herein the frame transmitted
from the AP 210 is represented as an HE TB FD PPDU. That is, the AP
210 transmits a frame to STA 2 220-2 while receiving frames from
STA 1 220-1 and STA n 220-n in the same time period (full-duplex
communication). In FIG. 5A, a downlink constituting the full-duplex
communication is represented by a thick solid line. The AP 210
synchronizes downlink and uplink and then performs downlink
transmission. The AP 210 transmits an HE TB FD PPDU on the basis of
the reference frame transmitted by the AP 210 or on the basis of
timing information included in the reference frame.
[0052] FIG. 6 illustrates another example process of performing
full-duplex communication in a WLAN environment. FIG. 6 may be an
example process of the BSS of FIG. 5A. This example will be
described in time order.
[0053] The AP 210 transmits an MU-RTS frame to STA 1 220-1 and STA
n 220-n at time T=t0. In response to the MU-RTS frame, STA 1 220-1
and STA n 220-n commence the transmission of a CTS frame at time
T=t1 respectively in OFDMA modulation way. After receiving the CTS
response, the AP can perform the following steps. The MU-RTS/CTS
exchange corresponds to a pre-operation for MU transmission. This
process is optional, and thus may not be an operation that must be
performed before the DL MU PPDU.
[0054] The AP 210 transmits the DL MU PPDU to STA 1 220-1 and STA n
220-n at time T=t2. The DL MU PPDU corresponds to the
above-described reference frame. The DL MU PPDU may include a TRS
control field. The DL MU PPDU may include RU allocation information
for STAs.
When the reference frame is received, STA 1 220-1 and STA n 220-n
may transmit an HE TB PPDU through allocated RUs along with an ACK
at time T=t3. STA 1 220-1 and STA n 220-n may transmit an HE TB
PPDU to the AP in the same time period. STA 1 220-1 and STA n 220-n
may transmit an HE TB PPDU at a certain timing which is the SIFS
time boundary, after the end of a received reference frame. That
is, STA 1 220-1 and STA n 220-n may synchronize frames to be
transmitted by using the received DL MU PPDU. A SIFS is the time
from the end of the last symbol, or signal extension if present, of
the previous frame to the beginning of the first symbol of the
preamble of the subsequent frame. For example, if the control frame
is a response frame of a previous frame, the WLAN device transmits
the control frame without performing backoff if a SIFS has
elapsed.
[0055] Meanwhile, the AP 210 may transmit an HE TB FD PPDU to STA 2
220-2 at time T=t3. That is, the AP 210 transmits a frame to STA 2
220-2 while receiving frames from STA 1 220-1 and STA n 220-n in
the same time period (full-duplex communication). The AP 210
transmits an HE TB FD PPDU on the basis of the DL MU PPDU
transmitted by the AP 210 or on the basis of timing information
included in the DL MU PPDU. Referring to FIG. 6, a null portion are
shown in front of the HE TB FD PPDU at time T=t3. This will be
described with FIG. 8.
[0056] In response to the reception of the HE TB PPDU, the AP 210
may transmit a BlockAck frame to STA 1 220-1 and STA n 220-n at
time T=t4. The transmission of the BlockAck frame may be optional.
Also, at time T=t4, STA 2 220-2 may transmit an ACK for the HE TB
FD PPDU corresponding to time T=t3.
[0057] FIG. 7 is still another example process of performing
full-duplex communication in a WLAN environment. FIG. 7A
illustrates a BSS 300 that performs full-duplex communication in a
WLAN environment. The BSS 300 includes a single AP 310 and n STAs
320-1, 320-2, . . . , 320-n. The AP 310 is an AP capable of
full-duplex communication (hereinafter referred to as an FD-capable
AP). The FD-capable AP may be an AP having a function of cancelling
self-interference (SI) caused by a signal transmitted by the AP
itself. STA 1 320-1 and STA n 320-n are STAs capable of full-duplex
communication. The FD-capable STA may be an STA having a function
of cancelling self-interference (SI) caused by a signal transmitted
by the STA itself. The SI cancellation technology can be
implemented in various ways.
[0058] FIG. 7B illustrates an example in which full-duplex
communication is performed in the BSS 300. This example will be
described in time order. The AP 310 transmits a reference frame to
STA 1 320-1 and STA n 320-n. The reference frame may be the
above-described trigger frame. Also, the reference frame may
include a TRS control field. The reference frame may include RU
allocation information for OFDMA communication.
[0059] When the reference frame is received, STA 1 320-1 and STA n
320-n transmit an HE TB PPDU through allocated RUs. STA 1 320-1 and
STA n 320-n may each transmit an HE TB PPDU to the AP in the same
time period. STA 1 320-1 and STA n 320-n may transmit an HE TB PPDU
at a certain timing on the basis of the received reference frame.
That is, STA 1 320-1 and STA n 320-n may synchronize frames to be
transmitted by using the received reference frame.
[0060] Meanwhile, the AP 310 may transmit an HE TB FD PPDU to STA 1
320-1 and STA n 320-n at or within a time period in which the HE TB
PPDU is received (full-duplex communication). In FIG. 7A, a
downlink constituting the full-duplex communication is represented
by a thick solid line. The AP 310 synchronizes downlink and uplink
and then performs downlink transmission. The AP 310 transmits an HE
TB FD PPDU on the basis of the reference frame transmitted by the
AP 310 or on the basis of timing information included in the
reference frame.
[0061] Similarly, to FIG. 6, although not shown in FIG. 7B, the
MU-RTS/CTS exchange may be performed before the reference frame is
transmitted. Also, after the HE TB FD PPDU is transmitted, the AP
310 may transmit a BlockAck frame in response to the reception of
the HE TB PPDU. Also, STA 1 320-1 and STA n 320-n may transmit an
ACK for the HE TB FD PPDU.
[0062] FIG. 8 is an example packet for full-duplex communication.
An HE TB PPDU structure defined in IEEE 802.11ax is shown in an
upper portion of FIG. 8. An example HE TB FD PPDU structure is
shown in a lower portion of FIG. 8. An example in which the HE TB
PPDU and the HE TB FD PPDU are placed in the same time period is
shown. FIG. 8 is an example in which HE TB PPDU (uplink) and HE TB
FD PPDU (downlink) constituting full-duplex communication are
placed in the same time period.
[0063] As described above, the HE TB PPDU may be transmitted in a
certain time period on the basis of a reference frame (trigger
framing) sent by AP. In this case, the HE TB PPDU may be
transmitted after a short IFS (SIFS) time interval from the
reference frame end. The SIFS refers to the shortest one among
inter-packet space time intervals between consecutive two packets
defined in the standard.
[0064] The HE TB PPDU can be divided into a non-HE portion and an
HE portion. The non-HE portion includes a L-short training field
(STF), L-long training field (LTF), and L-signal information field
(SIG). These fields are defined in a conventional WLAN standard.
802.11ax uses the same fields as described in the WLAN standard for
the purpose of compatibility with conventional WLAN. The L-STF is a
short training sequence and is used for packet detection and
automatic gain adjustment (AGC). The L-LTF is a relatively long
training sequence and is used for channel estimation. The L-SIG may
include control information corresponding to decoding of PSDU or
the like.
[0065] RL-SIG, in which a conventional legacy L-SIG is repeated, is
a field for HE PPDU detection. HE-SIG-A includes MCS, a frequency
bandwidth, the number of spatial streams (NSTS), and parameters for
frame decoding. HE-STF and HE-LTF include a training sequence for
multiple-input and multiple-output (MIMO). The HE-STF is mainly
used to measure automatic gain adjustment during MIMO transmission.
The HE-LTF is used to estimate a MIMO channel. The HE-LTF has a
variable length. Data field includes an encoder/decoder scrambler
and an encoded MAC frame. PE is an extension field.
[0066] The HE TB PPDU can be divided into a pre-HE modulated field
and an HE modulated field. HE PHY can support DFT periods of 3.2
.mu.s and 12.8 .mu.s for the pre-HE modulated field and the HE
modulated filed of the HE PPDU, respectively.
[0067] In the HE TB FD PPDU, a modulated signal may be transmitted
in a region in which the HE modulated field of the HE TB PPDU is
started in the same time period. The HE TB FD PPDU may be aligned
to the HE modulated field of the HE TB PPDU in the same time
period. A null portion may be a signal field in which no signal is
transmitted. Also, the null portion may be a signal field for
transmitting information that does not affect the demodulation
processing of the HE TB PPDU by the AP. The HE TB FD PPDU may be
transmitted in a time period in which the AP receives the HE TB
PPDU, and the HE TB FD PPDU is intended to be transmitted in a
period that does not affect the processing of the received HE TB
PPDU. That is, the AP controls a time to transmit the HE TB FD PPDU
such that the transmission of the HE TB FD PPDU does not disturb
the transmission of the HE TB PPDU. The AP ensures that the
training process for the received HE TB PPDU is normally
performed.
[0068] A lower portion of FIG. 8 illustrates an HE TB FD PPDU
structure. The HE TB FD PPDU structure shown in FIG. 8 is an
example, and the HE TB FD PPDU may have another structure. FIG. 8
illustrates an example including FD-STF, FD-LTF, FD-SIG, and the
like. In this case, the fields may perform functions similar to
those of the HE-STF, HE-LTF, and HE-SIG.
[0069] FIG. 9 illustrates example resources to be allocated for
full-duplex communication. FIG. 9A illustrates an example in which
individual RUs are allocated to uplink and downlink. As described
in FIG. 5, when an FD-capable AP performs full-duplex communication
with any STA, the AP and the STA may use different RUs.
[0070] FIG. 9B illustrates an example in which a common RU is
allocated to uplink and downlink. FIG. 9B illustrates a case in
which a pair of AP and STA uses a single common RU. As shown in
FIG. 7, when an FD-capable AP and an FD-capable STA perform
full-duplex communication, the pair may use a common RU. The AP may
deliver information regarding the RU through the reference frame
(the trigger frame). FIG. 9B illustrates an example in which the AP
of FIG. 7 and STA 1 use a common RU and the AP of FIG. 7 and STA n
use a common RU.
[0071] FIG. 10 illustrates an example of resource allocation for
full-duplex communication. FIG. 10 illustrates an example in which
an AP receives an HE TB PPDU from two STAs (STA 1 and STA n) at a
specific time and transmits an HE TB FD PPDU to an STA (STA1, STA
n, or another STA) at the same specific time. FIG. 10 illustrates a
40-MHz band, as an example.
[0072] FIG. 10A illustrates an example of resource allocation for
the HE TB PPDU transmitted by STA 1. FIG. 10B illustrates an
example of resource allocation for the HE TB FD PPDU transmitted by
the AP. In the HE TB FD PPDU, a signal is transmitted only in the
HE modulated field as described above. FIG. 10C illustrates an
example of resource allocation for the HE TB PPDU transmitted by
STA n. FIG. 10D illustrates an example in which resources are
allocated to frames transmitted by STA 1, STA n, and the AP in the
same time period. Referring to FIG. 10, it shows that three
individual frames may be simultaneously transmitted on two channels
of 20 MHz.
[0073] When 242-tone RU (20 MHz) or less-tone RU is allocated, a
pre-HE modulated field is generally transmitted at corresponding 20
MHz (indicated by {circle around (1)} and {circle around (2)} in
FIG. 10). However, in some cases, the pre-HE modulated field may be
transmitted at 40 MHz including a corresponding 20 MHz channel (not
shown).
[0074] FIG. 11 illustrates an example reference frame. The
reference frame may be a trigger frame defined in IEEE 802.11ax.
The reference frame may include information regarding RUs for
full-duplex communication (FD). Resource allocation information for
the FD communication may be implemented in various ways. FIG. 11
illustrates an example frame to be used in 802.11ax. A description
of information included in a MAC header, that is, a description of
the same part as a conventional WLAN header will be omitted.
[0075] HT Control includes an aggregated control subfield. In FIG.
11, a part (A) indicates an example in which a field for FD
resource information is separately added to the control subfield.
The part (A) includes Control ID, FD, and Reserved field. Control
ID is an identifier about information indicated by the control
subfield. When Control ID is configured to set a value indicating
FD resource information, FD field may include resource information
for the FD communication. In FIG. 11, a part (B) indicates another
example control subfield. In the part (B), when Control ID is
configured to set a value indicating FD resource information, the
resource information for the FD may be included in Control
Information field. Alternatively, when Control ID is a specific
value to which any current use is not allocated, the resource
information for the FD feature may be included in Control
Information field.
[0076] FIG. 11 illustrates an example in which the FD resource
information is conveyed using HT Control field. In some cases, the
reference frame may convey the FD resource information through
another field or an FD-dedicated field.
[0077] FIG. 12 illustrates an example block diagram of an AP and an
STA. FIG. 12 illustrates a BSS including a single AP 410 and a
single STA 420, as an example. It is assumed that the AP 410 and
the STA 420 are FD-capable apparatuses.
[0078] The AP 410 includes a storage device 411, a memory 412, a
computing device 413, and a communication device 414. In FIG. 12,
the storage device 411, the memory 412, the computing device 413,
and the communication device 414 are shown as separate independent
elements. At least any combination merged with two or more
components among the storage device, the memory, the computing
device and the communication device 414 may be configured in an
integrated manner.
[0079] The storage device 411 stores a source code or program for
WLAN communication with the STA. The storage device 411 stores
information for high-efficiency WLAN communication by default.
Also, the storage device 411 may store information for the
above-described full-duplex communication. The storage device 411
may be implemented in the form of a hard disk, a read-only memory
(ROM), a flash memory, or the like. The storage device 411 may
store data to be transmitted and data received.
[0080] The memory 412 may temporarily store data generated while
the AP 410 performs communication.
[0081] The communication device 414 refers to an element for
transmitting and receiving data through WLAN communication. The
communication device 414 may include at least one antenna and a
communication module. The communication device 414 may include a
plurality of antennas for MIMO. The communication device 414 may
receive packets from at least one STA. Also, the communication
device 414 may transmit packets to at least one STA. The
communication device 414 may receive program update information
from an external object.
[0082] The computing device 413 may transmit and receive data
(packets) using a program stored in the storage device 411. The
computing device 413 may transmit a reference frame to at least one
STA through the communication device 414 according to a received
command or a generated command. The communication device 414 may
receive an uplink frame from an STA in a specific time period
determined on the basis of the reference frame. The computing
device 413 may transmit a downlink frame to an STA through the
communication device 414 in a part time of the time period in which
the downlink frame is received. In this case, the computing device
413 may transmit a downlink frame to the STA having transmitted the
uplink or another STA. In this case, the computing device 413 may
perform control such that the downlink frame is transmitted to an
HE modulated field of an uplink frame. The computing device 413 may
be a device for processing data and performing certain computation,
such as a processor, an AP, and a chip with an embedded
program.
[0083] For example, the AP 410 may transmit the DL MU PPDU to the
STA 420. The AP 410 may receive the HE TB PPDU from the STA 420in a
specific time period. In this case, the AP 410 may transmit the HE
TB FD PPDU to the STA 420 or another STA in a period in which an HE
TB PPDU HE modulated field is transmitted.
[0084] Although not shown in FIG. 12, the AP 410 may include an
element for cancelling SI to perform full-duplex communication.
[0085] The STA 420 includes a storage device 421, a memory 422, a
computing device 423, an interface device 424, and a communication
device 425. In FIG. 12, the storage device 421, the memory 422, the
computing device 423, the interface device 424, and the
communication device 425 are shown as separate independent
elements. At least any combination merged with two or more
components among the storage device 421, the memory 422, the
computing device 423, the interface device 424 and the
communication device 425 may be configured in an integrated
manner.
[0086] The storage device 421 stores a source code or program for
WLAN communication with the AP. The storage device 421 stores
information for high-efficiency WLAN communication by default.
Also, the storage device 421 may store information for the
above-described full-duplex communication. The storage device 421
may be implemented in the form of a hard disk, a ROM, a flash
memory, or the like. The storage device 421 may store data to be
transmitted and data received.
[0087] The memory 422 may temporarily store data generated while
the STA 420 performs communication.
[0088] The interface device 424 is a device for receiving certain
commands or data from the outside. The interface device 424 may
receive certain commands or data from an external storage device or
an input device that is physically connected to the interface
device 424. The interface device 424 may receive a command for
communication with the AP 410, control information, data to be
transmitted, or the like.
[0089] The communication device 425 refers to an element for
transmitting and receiving data through WLAN communication. The
communication device 425 may include at least one antenna and a
communication module. The communication device 425 may include a
plurality of antennas for MIMO. The communication device 425 may
receive packets from the AP. Also, the communication device 425 may
transmit packets to the AP. The communication device 425 may
receive program update information from an external object.
[0090] The computing device 423 may transmit and receive data
(packets) using a program stored in the storage device 421. The
communication device 425 may receive a reference frame from the AP
410. The computing device 423 may determine a specific time period
on the time basis of the reference frame. The computing device 423
may transmit an uplink frame to the AP through the communication
device 425 in the determined specific time period. The computing
device 423 may be a device for processing data and performing
certain computation, such as a processor, an AP, and a chip with an
embedded program.
[0091] The communication device 425 may receive a downlink frame
from the AP 410 in a part time of the period in which the uplink
frame is transmitted. In this case, the downlink frame may be
received in a region where an HE modulated field of the uplink
frame is placed. The computing device 423 may control the
communication device 425 such that the downlink frame is received
at the same time as the uplink frame is transmitted.
[0092] For example, the STA 420 may receive the DL MU PPDU from the
AP 410. The STA 420 may transmit the HE TB PPDU in a specific time
period on the basis of the DL MU PPDU. The STA 420 may receive the
HE TB FD PPDU from the AP 410 while transmitting the HE TB PPDU.
The HE TB FD PPDU may be received in a period in which the HE
modulated field of the HE TB PPDU is transmitted.
[0093] Although not shown in FIG. 12, the STA 420 may include an
element for cancelling SI to perform full-duplex communication.
[0094] Also, the above-described full-duplex communication method
may be implemented using a program (or application) including an
executable algorithm that may be executed by a computer. The
full-duplex communication method may be embedded into an AP and an
STA.
[0095] The program may be stored and provided in a non-transitory
computer readable medium. The non-transitory computer readable
medium refers not to a medium that temporarily stores data such as
a register, a cache, and a memory but to a medium that
semi-permanently stores data and that is readable by a device.
Specifically, the above-described various applications or programs
may be provided while being stored in a non-transitory computer
readable medium such as a compact disc (CD), a digital versatile
disc (DVD), a hard disk, a Blu-ray disc, a Universal Serial Bus
(USB), a memory card, a read-only memory (ROM), etc.
[0096] A number of examples have been described above.
Nevertheless, it will be understood that various modifications may
be made. For example, suitable results may be achieved if the
described techniques are performed in a different order and/or if
components in a described system, architecture, device, or circuit
are combined in a different manner and/or replaced or supplemented
by other components or their equivalents. Accordingly, other
implementations are within the scope of the following claims.
* * * * *